1 Various methods have been used for the separation and quantitation of serum li
ID: 85284 • Letter: 1
Question
1
Various methods have been used for the separation and quantitation of serum lipoproteins. Give at least two of the methodologies and the principle of the methodology.
2
CSF protein levels are important in the body as well as serum proteins. These levels may correlate with different clinical conditions if increased or decreased.
There are two calculations which are helpful in evaluating CSF IgG. Please give both calculations, what their reference ranges are, and what increases or decreases in each might correlate with clinically.
3
A 40 yr old man has developed some dermatologic issues over the past 3 years along with hepatic enlargement, lack of coagulation factors, increases in liver enzymes. He states he sometimes feels "confused". His CBC indicates a pancytopenia and his blood smear displays some basophilic stippling. He also notes that he sometimes experiences nausea accompanied by abdominal pains. Further patient history: man has lived in the same town for 20 yrs, worked at the same job in a wood processing plant since he was 25 and lives on a rural farm. Indicate which trace element might be responsible for this man's condition and why.
Explanation / Answer
1.Separation and quantitation of serum lipoproteins.
Several techniques are used for separating and quantitating lipoproteins in human serum. First the lipoproteins are separated into one or more of the major lipoprotein classes: very-low-density lipoproteins (VLDL), low-density lipoproteins (LDL), and high-density lipoproteins (HDL) using techniques like ultracentrifugation, electrophoresis, chromatographic methods (gel filtration, affinity), selective precipitation with polyanion/divalent cation reagents, homogeneous immunoassays, and by nuclear magnetic resonance. The lipoprotein concentration in each fraction is then quantitated according to their cholesterol content or summed content of cholesterol, triglycerides, phospholipids, and protein, or more recently using antibodies specific for their apolipoprotein (apo) content.
1. Size-exclusion liquid chromatography and spectrophotometry: Here, components of human serum are separated on the basis of differences in relative molecular mass by HPLC. The lipoproteins in fractions of the eluate can then be quantitated by conventional chemical and enzymatic methods using spectrophotometry.
2. Proton nuclear magnetic resonance (NMR) spectroscopy: Here no physical separation of the lipoproteins is required. The NMR spectral properties of each lipoprotein subclass are sufficiently distinct and reproducible and this property is exploited.
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